This invention relates to the discovery and asexual propagation of a new variety of grapevine as herein described and illustrated. The new variety ‘Sugrathirtythree’ was first hybridized by David W. Cain and Michael J. Striem in Wasco, Kern County, Calif., the variety being originated by controlled hybridization and subsequent culture of seed traces and embryo rescue procedures.
The new variety ‘Sugrathirtythree’ is characterized by producing late-season ripening, green-yellowish, seedless grapes with mild neutral flavor. The berries have a naturally medium size and an elliptic shape, crisp flesh texture, medium and up sugar content and excellent eating quality. The new variety ‘Sugrathirtythree’ is exceptional with its late ripening habit, as the grapes ripen after any other seedless grape cultivars grown and marketed commercially in California. Furthermore, the bunches are able to stay on the vine for a month or more, while still maintaining commercial harvest quality.
The seed parent is the varietal selection ‘92147-050-238’ (unpatented) and the pollen parent is the varietal selection ‘92187-055-030’ (unpatented). The parent varieties were first crossed in May, 1999, by David W. Cain and Michael J. Striem. The new variety was created by hybridization of two “seedless” grapes possessing small, abortive, vestigial ovules. From the initial population of hybrid ovules, embryo rescue methods were used to produce a population from which the present variety was selected. The date of first sowing was August, 1999, and the date of first flowering was May, 2001.
The new variety ‘Sugrathirtythree’ was first asexually propagated in December, 2001, in Wasco, Kern County, Calif., by Dr. Michael Striem using hardwood cuttings.
The new variety ‘Sugrathirtythree’ resembles its seed parent ‘92147-050-238’ in characteristics such as berry color and shape. However, ‘Sugrathirtythree’ has a much larger natural berry size (approximately 4.55 grams) as compared to the natural berry size of the seed parent (approximately 3.35 grams). Additionally, the seed trace of ‘Sugrathirtythree’ is very small and soft, whereas the seed parent ‘92147-050-238’ has a noticeable, dark and hard seed trace.
The new variety ‘Sugrathirtythree’ resembles its pollen parent ‘92187-055-030’ in characteristics such as berry color and shape. However, ‘Sugrathirtythree’ has a much larger natural berry size (approximately 4.55 grams) as compared to the natural berry size of the pollen parent (approximately 4.26 grams). Furthermore, while the berries of the pollen parent turn brown when exposed to direct sunshine, the berries of the new variety ‘Sugrathirtythree’ remain light-green with a milky-creamy/opaque look, turning slightly yellowish at the end of the harvest season.
The new variety ‘Sugrathirtythree’ resembles the comparable variety ‘Sugraone’ (U.S. Pat. No. 3,106) in its appearance, bunch structure and berry shape. However, ‘Sugrathirtythree’ ripens about 7-9 weeks later than ‘Sugraone’. In addition, the new variety ‘Sugrathirtytree’ develops higher sugar levels than ‘Sugraone’ at harvest.
The new ‘Sugrathirtythree’ variety has been shown to maintain its distinguishing characteristics through successive asexual propagations by, for example, cuttings.
It is to be understood that variations of the usual magnitude from the described above may occur with changes in growing conditions, irrigation, fertilization, pruning, management and climatic variations.